In an internal combustion-type engine, the carburetor mixes controlled quantities of filtered air and fuel and feeds the resultant mixture to the intake manifold, from which it is distributed to the cylinder for combustion. It has been recognized by those skilled in the art that during compression of the fuel-air mixture by the piston in a particular cylinder, certain quantities of blow-by vapors leak into the crankcase of the engine and become trapped therein with contaminants such as oil vapors emitted by heated engine-lubricating oil.
Modern automobile engines have been equipped with a positive crankcase ventilation (PCV) system which is disposed in a blow-by gas recirculation line connecting the crankcase and the intake manifold to recycle the contaminated blow-by vapors back into the combustion chamber. In such a system, a stream of fresh air is directed into the engine interior wherein it recirculates, picking up the vapor therein. The contaminated blow-by vapor then leaves the crankcase through a PCV valve and is conducted by conduit means to the intake manifold, wherein it mixes with the fuel-air mixture provided by the carburetor and is distributed to the cylinders for combustion.
It has also been recognized that the oil and other contaminants mixing with the blow-by vapors in the crankcase and, thereafter, reaching the intake manifold and combustion cylinders, has a number of undesirable effects on engine performance, including fouling of spark plugs through accumulation thereon of non-combustible residues, increased exhaust emissions due to the presence of unburned vapors, and decreased gas mileage as a result of incomplete combustion and the necessity of enriching the fuel-air mixture to off-set the loss of power therefrom.
In my earlier patent, U.S. Pat. No. 4,136,650 issued Jan. 30, 1979, I have provided a crankcase oil recovery system for separating oil from the recycled blow-by vapors. While this system is satisfactory, an improved, simpler, less costly system, as well as one which is more effective in separating oil, is desired.